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Detailed Analysis of Dissimilar Welding Process Between Aluminum Sheets and Nickel Sheets
Jul 01,2026
Dissimilar welding between aluminum sheets and nickel sheets is a critical process in the manufacturing of new energy vehicle power battery flexible connections and electrical busbars. The key pain points of welding these two metals are listed below:
1.Oxide film obstruction: The hard aluminum oxide film on the surface of aluminum sheets blocks the bonding between aluminum and nickel atoms, easily resulting in cold solder joints and incomplete penetration.
2.Brittle intermetallic compound formation: Hard and brittle intermetallic compounds tend to generate during welding, forming brittle layers that cause weld cracking.
3.Unbalanced thermal stress: There are significant differences in melting point, thermal expansion coefficient and thermal conductivity between the two materials. Severe thermal stress arises during heating and cooling, leading to workpiece deformation and weld peeling.
4.Uneven fusion: Aluminum has a low melting point and high thermal conductivity, while nickel features a high melting point and low thermal conductivity. Excessive melting of aluminum and insufficient melting of nickel often occur during welding, resulting in low joint strength.
The optimal welding method is polymer diffusion welding. Its working principle requires no additional solder, flux or shielding gas. Under high temperature and high pressure, atoms on the surfaces of aluminum sheets and nickel sheets interpenetrate and fuse to form tightly bonded welded joints.
Advantages of Polymer Diffusion Welding
1.Reliable transitional connection: Aluminum sheets cannot be directly welded to battery cells, terminals and other components. Welding nickel sheets creates a stable transition layer for firmer overall assembly.
2.Stable electrical conductivity: Tight bonding after welding delivers low contact resistance and smooth current transmission with minimal heat generation, making it suitable for high-current scenarios such as power batteries and energy storage systems.
3.High joint strength and anti-falloff performance: Atomic interdiffusion produces strong tensile resistance, effectively preventing cracking and desoldering during service with superior vibration resistance and long-term safety.
4.Eco-friendly without solder or flux: No extra solder, flux or shielding gas is required in the welding process. No welding slag residue leaves clean finished products and eliminates post-welding cleaning procedures.
5.Superior surface finish: Smooth and flat welding surfaces free of burrs, wrinkles and bulges, enabling direct assembly of finished parts.
6.Enhanced corrosion resistance and service life: Nickel itself boasts excellent corrosion resistance. Dense welded joints reduce oxidation and galvanic corrosion, extending the service life of flexible connections and busbars.
7.High production efficiency for mass manufacturing: Fast welding speed, stable processes and high yield rates fit large-scale production demands of the new energy and power industries.
Specific Welding Procedures
1.Base material surface treatment: Wipe the welding surfaces of aluminum sheets and nickel sheets thoroughly to remove oil stains, dust and surface oxide layers, ensuring flat and clean contact surfaces.
2.Stacking and positioning: Align and stack aluminum sheets and nickel sheets in accordance with product specifications, then temporarily fix them with fixtures or spot welders to avoid offset during welding.
3.Clamping between upper and lower graphite molds: Place the positioned aluminum-nickel assembly between the upper and lower graphite molds of the polymer diffusion welder and adjust the position accurately.
4.Welding parameter setting: Adjust equipment pressure, temperature, welding duration and other parameters based on material thickness to match the requirements of aluminum-nickel welding.
5.High-temperature high-pressure welding: Start the equipment for automatic graphite compression. Aluminum and nickel sheets complete metallurgical bonding under high temperature and high pressure.
6.Post-welding cooling and unloading: Allow workpieces to cool naturally after welding before removing them from graphite molds to avoid deformation or cracking caused by high-temperature unloading.
7.Finished product inspection: Check welding surfaces for flatness, cold solder joints and cracks. Conduct tensile and adhesion tests to confirm qualification before proceeding to subsequent processes.
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Wuxi HAIFEI Intelligent Equipment Co., Ltd.
Wuxi HAIFEI Welding Equipment Co., Ltd.
Add: 28 Shuiyun Road, Yuecheng, Jiangyin, Jiangsu Province, China. (Postal Code: 214404)
Mobile: +86 18151507807
Email: info@jshaifei.com